Lately, when trying to work outside in my garden, I am plagued with small insects that swarm around my head, get into my eyes and bite my ears, painfully I might add. They bother my dog so much, she won’t even come outside with me and my neighbor told me they killed one of his chickens. What are these and what can we do?
Most of these flies are 1/8-inch long or less and their second body region or thorax is very convex giving a humped appearance, hence the nickname “buffalo gnat.” Only the females bite looking for a blood meal in order to lay her eggs. They require moving water to breed and develop as the water movement provides them with oxygen and food. The female will fly 7 to 10 miles looking for a meal and then will return to the water to lay her eggs where the larvae attach themselves to submerged objects, feed and molt six times before emerging from the water as adults. Females can live from a few days to more than 3 months until conditions are right to mate.
Yard fogging or spraying is not recommended or effective for several reasons. Black flies feed during the day, a time when fogging or spraying is the least effective and it does nothing to control the pest because it doesn’t destroy the larvae at its source. There is a natural control, Bacillus thurgiensis israeliensis (Bti), which can successfully reduce populations of larvae when applied to moving water sources, but needs to be done on a larger scale than homeowners can accomplish.
To protect yourself and your animals it is important to understand the way these bugs work. The flies are attracted to us or our animals by the carbon dioxide and moisture we exhale, dark colors, and perspiration. They prefer calm, sunny days and will not fly at night or on windy days. They are daytime, outdoor feeders so the best form of protection is avoidance. If you do venture outdoors to work in your garden wear light colored clothes and long sleeves and a hat with netting like beekeepers use to further protect your face and neck. Repellents such as DEET and vanilla extract or vanilla scented sprays can offer some relief against them, but the effect is usually only temporary. Pets are at a much lower risk of being bitten if kept indoors during the day, even if the building is not fly-proof. For chickens and other livestock, keep them inside in a darkened barn during the day and use fans to prevent overheating and simulate wind.